After workers have finished removing the concrete base from the structure, Able Demolition will leave and the FBI will search beneath the barn's foundation, the company said.

The government eventually will have to replace the barn, or any other structures it removes, and pay for any damage to the Hidden Dreams Farm in Milford Township, Michigan, about 30 miles northwest of Detroit.

The FBI paid Able $6,000 to tear down the barn, the company said.

The FBI has been searching for the remains of the former union boss since May 17, after receiving what an agent called "a fairly credible lead."

Wells, who lived on the farm on the 1970s, told the FBI that he saw two men use a backhoe to dig a hole where agents are now searching, according to the Free Press. Wells said he recalls the men putting what appeared to be a rolled-up carpet into the hole the day after Hoffa disappeared, the paper reported.

Hoffa's disappearance

Hoffa was last seen at Machus Red Fox restaurant in nearby Bloomfield Township. He was reportedly there to meet Detroit mob street enforcer Anthony Giacalone and New Jersey Teamsters official Anthony Provenzano. (Who is Jimmy Hoffa?)

Hoffa believed Giacalone had set up the meeting to help settle a feud between Hoffa and Provenzano, but Hoffa was the only one who showed up for the meeting, according to the FBI.

Giacalone and Provenzano later told the FBI that no meeting had been scheduled.

The FBI said Hoffa's disappearance could have been linked to his efforts to regain power in the Teamsters after he was released from prison.

After serving time for jury tampering and fraud at a federal penitentiary in Lewisburg, Pennsylvania, Hoffa was pardoned by President Richard Nixon on December 23, 1971.

Nixon included in the pardon a condition that Hoffa "not engage in direct or indirect management of any labor organization" until at least March 1980.

Hoffa was 62 at the time of his disappearance.

In September 2001 the FBI found DNA that linked Hoffa to a car that agents suspected was used in his disappearance.

In May 2004 authorities from Oakland County, Michigan, removed floorboards from a Detroit home and found blood that they thought might be linked to Hoffa's disappearance. Milford Township is in Oakland County.

Authorities went to the Detroit home in 2004 after a biography of former Teamsters official Frank Sheehan stated that Sheehan shot Hoffa in the home, just beyond the front door.

Investigators ruled blood found in the house was not Hoffa's. The FBI has a sample of his DNA from a hair brush.

Sheehan, who was considered a confidant of Hoffa, died in December 2003. Provenzano died in 1988 after being convicted in another murder case, and Giacalone died of kidney failure in 2002 at age 82.

Hoffa's son, James P. Hoffa, is the current president of the Teamsters.